<?php
/**
 * GitHub-based plugin updater.
 *
 * Hooks into WordPress's native update system so the plugin receives update
 * notifications sourced from GitHub releases rather than the wp.org directory.
 *
 * @package LogoSoup\Support
 */

namespace LogoSoup\Support;

/**
 * Enables automatic plugin updates sourced from GitHub releases.
 */
class GitHub_Updater {

	const GITHUB_USER   = 'Vincent-Design-Inc';
	const GITHUB_REPO   = 'Logo-Soup';
	const TRANSIENT     = 'logo_soup_github_release';
	const TRANSIENT_TTL = 43200; // 12 hours.

	/**
	 * Plugin slug (relative path from plugins dir, e.g. logo-soup/logo-soup.php).
	 *
	 * @var string
	 */
	private $plugin_slug;

	/**
	 * Absolute path to the main plugin file.
	 *
	 * @var string
	 */
	private $plugin_file;

	/**
	 * Currently installed version, read from plugin headers.
	 *
	 * @var string
	 */
	private $current_version;

	/**
	 * Constructor.
	 *
	 * @param string $plugin_file Absolute path to the main plugin file.
	 */
	public function __construct( $plugin_file ) {
		$this->plugin_file = $plugin_file;
		$this->plugin_slug = plugin_basename( $plugin_file );

		$headers               = get_file_data( $plugin_file, array( 'Version' => 'Version' ) );
		$this->current_version = ! empty( $headers['Version'] ) ? $headers['Version'] : '0.0.0';
	}

	/**
	 * Register WordPress hooks.
	 *
	 * @return void
	 */
	public function register() {
		add_filter( 'pre_set_site_transient_update_plugins', array( $this, 'inject_update' ) );
		add_filter( 'plugins_api', array( $this, 'plugin_info' ), 20, 3 );
		add_filter( 'upgrader_process_complete', array( $this, 'purge_transient' ), 10, 2 );
	}

	/**
	 * Inject update data into WordPress's update_plugins transient.
	 *
	 * @param object $transient The update_plugins transient value.
	 * @return object
	 */
	public function inject_update( $transient ) {
		if ( empty( $transient->checked ) ) {
			return $transient;
		}

		$release = $this->fetch_latest_release();

		if ( ! $release ) {
			return $transient;
		}

		$remote_version = ltrim( $release['tag_name'], 'v' );

		if ( version_compare( $this->current_version, $remote_version, '>=' ) ) {
			return $transient;
		}

		$download_url = $this->get_download_url( $release );

		if ( ! $download_url ) {
			return $transient;
		}

		$transient->response[ $this->plugin_slug ] = (object) array(
			'slug'        => dirname( $this->plugin_slug ),
			'plugin'      => $this->plugin_slug,
			'new_version' => $remote_version,
			'url'         => 'https://github.com/' . self::GITHUB_USER . '/' . self::GITHUB_REPO,
			'package'     => $download_url,
		);

		return $transient;
	}

	/**
	 * Supply plugin info for the "View version details" modal in the admin.
	 *
	 * @param false|object|array $result The result object or array, or false.
	 * @param string             $action The type of info being requested.
	 * @param object             $args   Plugin API arguments.
	 * @return false|object
	 */
	public function plugin_info( $result, $action, $args ) {
		if ( 'plugin_information' !== $action ) {
			return $result;
		}

		if ( ! isset( $args->slug ) || dirname( $this->plugin_slug ) !== $args->slug ) {
			return $result;
		}

		$release = $this->fetch_latest_release();

		if ( ! $release ) {
			return $result;
		}

		$remote_version = ltrim( $release['tag_name'], 'v' );
		$download_url   = $this->get_download_url( $release );
		$changelog      = ! empty( $release['body'] ) ? nl2br( esc_html( $release['body'] ) ) : '';

		return (object) array(
			'name'          => 'Logo Soup',
			'slug'          => dirname( $this->plugin_slug ),
			'version'       => $remote_version,
			'author'        => 'Vincent Design Inc',
			'homepage'      => 'https://github.com/' . self::GITHUB_USER . '/' . self::GITHUB_REPO,
			'download_link' => $download_url,
			'trunk'         => $download_url,
			'requires'      => '6.1',
			'requires_php'  => '7.4',
			'sections'      => array(
				'description' => esc_html__( 'Build balanced logo grids and marquees directly inside the WordPress block editor.', 'logo-soup' ),
				'changelog'   => $changelog,
			),
		);
	}

	/**
	 * Delete the cached release transient after a successful plugin update.
	 *
	 * @param \WP_Upgrader $upgrader  Upgrader instance.
	 * @param array        $hook_extra Extra data about the upgrade.
	 * @return void
	 */
	public function purge_transient( $upgrader, $hook_extra ) {
		if (
			! empty( $hook_extra['action'] ) &&
			'update' === $hook_extra['action'] &&
			! empty( $hook_extra['type'] ) &&
			'plugin' === $hook_extra['type'] &&
			! empty( $hook_extra['plugins'] ) &&
			in_array( $this->plugin_slug, (array) $hook_extra['plugins'], true )
		) {
			delete_transient( self::TRANSIENT );
		}
	}

	/**
	 * Fetch the latest GitHub release, with a 12-hour transient cache.
	 *
	 * @return array|null Decoded release data or null on failure.
	 */
	private function fetch_latest_release() {
		$cached = get_transient( self::TRANSIENT );

		if ( is_array( $cached ) ) {
			return $cached;
		}

		$url = sprintf(
			'https://api.github.com/repos/%s/%s/releases/latest',
			self::GITHUB_USER,
			self::GITHUB_REPO
		);

		$response = wp_remote_get(
			$url,
			array(
				'timeout'    => 10,
				'user-agent' => 'WordPress/' . get_bloginfo( 'version' ) . '; ' . get_bloginfo( 'url' ),
				'headers'    => array(
					'Accept' => 'application/vnd.github+json',
				),
			)
		);

		if ( is_wp_error( $response ) ) {
			return null;
		}

		if ( 200 !== wp_remote_retrieve_response_code( $response ) ) {
			return null;
		}

		$data = json_decode( wp_remote_retrieve_body( $response ), true );

		if ( ! is_array( $data ) || empty( $data['tag_name'] ) ) {
			return null;
		}

		set_transient( self::TRANSIENT, $data, self::TRANSIENT_TTL );

		return $data;
	}

	/**
	 * Extract the zip download URL from a release.
	 *
	 * Prefers an attached release asset (.zip); falls back to the auto-generated
	 * GitHub source zipball.
	 *
	 * @param array $release Decoded GitHub release data.
	 * @return string|null
	 */
	private function get_download_url( array $release ) {
		if ( ! empty( $release['assets'] ) && is_array( $release['assets'] ) ) {
			foreach ( $release['assets'] as $asset ) {
				if (
					isset( $asset['browser_download_url'] ) &&
					'.zip' === substr( $asset['browser_download_url'], -4 )
				) {
					return $asset['browser_download_url'];
				}
			}
		}

		return isset( $release['zipball_url'] ) ? $release['zipball_url'] : null;
	}
}